Is an Onion a Vegetable or Fruit?

In this article we look at whether an onion is a vegetable or fruit from a lot of different angles.

Are Onions a Fruit Botanically?

If you were to ask a botanist, “Hey, we were wondering if (specimen X) is a fruit or a vegetable,” the botanist would look at how specimen X develops on the plant.

If specimen X contains seeds, and especially if it’s a part of the plant that swells up after flowering, it is a fruit.

If specimen X is any other part of the plant, such as leaves, roots, stems, or the seeds themselves, then the botanist would rule that it is a vegetable.

Is it seed-bearing? No? Okay, it’s a vegetable.

The Fruit vs. Vegetable Debate Goes To Trial

Other produce have triggered the whole fruit-or-veggie discussion. The undisputed heavyweight champion of the conversation is the tomato.

The question went all the way to the Supreme Court. It wasn’t because some guys were hung up over fine details, it was because a businessman wanted to bump up his bottom line .

A tariff had been signed by the 21st president of the United States, Chester Arthur, that would affect all imported vegetables, but not fruits.

Depending on how the Supreme Court ruled a tomato should be classified, imported tomatoes would be taxed or not.

In the end the Supreme Court acknowledged that the tomato was botanically a fruit but in the end tomatoes were ruled a vegetable for two reasons.

  1. They were commonly called vegetables by merchants and buyers of the tomatoes in regular conversation.
  2. They were used culinarily as vegetables. In culinary use vegetables are considered a more savory or bland flavor and are commonly served as part of a main dish or side dish during the main course of the meal. Fruits are considered sweet or tart and are commonly served as desserts or snacks.

Are Onions Culturally Vegetables?

“Yes!” many will say with thunderous gusto. And, I’d agree with them. Even at their sweetest onions don’t remind me of any fruits I know.

We eat lots of fruits at breakfast, but never onions. I’d think if you asked 100 people whether an onion was a fruit or vegetable we’d get at least 96% agreeing they are a vegetable.

What’s the Dictionary Say?

Since we’re looking to define onions it makes sense to look up some definitions. What is Meriam & Webster’s opinion on the matter.

“onion – a widely cultivated Asian herb (Allium cepa) of the lily family with pungent edible bulbs”

“fruit – the usually edible reproductive body of a seed plant, especially one having a sweet pulp associated with the seed”

“vegetable – a usually herbaceous plant (such as the cabbage, bean, or potato) grown for an edible part that is usually eaten as part of a meal”


The definitions don’t exactly crack the case. I think reading between the lines the fact that it doesn’t fit the fruit definition in any way leans it towards being classified as a vegetable according to the dictionary.

Is an Onion a Fruit or Vegetable in Horticulture?

Horticulture is the practice of growing crops for human use through consumption or other uses. It differs from agriculture in that a wide variety of plants are grown and that they are grown on smaller scales.

In horticulture, a fruit is defined as a woody perennial. That is its branches are more woody than green and pliable, and the plant is a perennial that lives for more than a year or two. Blueberry bushes and fruit trees fit the bill.

A vegetable in horticulture is defined as a herbaceous annual. That means a plant with green pliable growth that completes its life cycle within a year.

An onion is a biennial plant, meaning it takes two years for an onion plant to complete its life cycle. Check out “Onion Plant Life Cycle” for more on that.

So based on all information at hand, I think the onion plant fits the horticulture definition of a vegetable more than a fruit. It’s a veggie!

Interesting Facts About Onions

  • Onions have been eaten by humans long before agriculture got its start in 10,000 B.C. They were collected from the wild by our prehistoric ancestors.
  • Sweet onions only have around 18% more sugar than other onion types. The reason that they taste so much sweeter is that they have around half of the sulfur content that other onions have. This low sulfur amount makes the taste sweet but also means they can’t store for as long.
  • Eating fesh parsley can get rid of onion breath.
  • Ancient Egyptians worshipped onions and thought they represented eternity. They were commonly buried with pharaohs to help them on the other side.
  • Onions can be used to increase blood circulation and have been thought to been an aphrodisiac in ancient India and Egyptian cultures. It’s said that you can increase blood flow to your feet by rubbing chopped onions on them.
  • Ancient Greek and Roman soldiers and gladiators would rub onion on their skin with the thought that it would give them increased speed and power!

You might also be interested in “How Do Onions Grow?“.

Please comment below with your own thoughts on whether onions are a fruit or vegetable.

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